Semiconductor memory with volatile and non-volatile memory cells

Abstract

The present invention relates to a semiconductor memory with a volatile memory device, in particular a DRAM memory device, and with a non-volatile memory device. The volatile memory device is electrically coupled with the non-volatile memory device, and the non-volatile memory device has a polymer memory device adapted to be switched between two states of information.

Description

CLAIMS FOR PRIORITY [0001] This application claims priority to German Application Nos. 10 2004 052 586.2 filed Oct. 29, 2004 and 10 2005 045 312.0 filed Sep. 22, 2005 which are incorporated herein, in their entirety, by reference. TECHNICAL FIELD OF THE INVENTION [0002] The invention relates to a semiconductor memory with a combination of volatile and non-volatile memory cells. The invention further relates to the operation, the design, and to differing layout concepts for a semiconductor memory with a combination of volatile memory cells and non-volatile polymer memory cells. BACKGROUND OF THE INVENTION [0003] A semiconductor memory device usually comprises a cell field consisting of a plurality of memory cells, and a matrix of column and line supply lines or word and bit lines, respectively. The memory cells are each positioned at the crosspoints of the electroconductive supply lines that are each electrically connected with the memory cell via an upper electrode or top electrode ...

AI Technical Summary

Benefits of technology

[0018] This way, on the one hand, the cell size of the memory is reduced since, depending on the embodiment, a reduced number of control gate lines or no control gate line at all is needed anymore. Due to the reduced number of control gate lines, a simpler operation is also achieved than in prior art. Furthermore, distinctly lower voltage values than with conventional semiconductor memories that are operated in combination with flash memory cells are required in the case of the inventive semiconductor memory. Another advantage of the inventive semiconductor memory consists in that the writing rate of a polymer memory is higher than that of a flash memory cell.

[0019] The present invention is primarily based on the combination of a volatile DRAM semiconductor memory with non-volatile polymer memory cells which enable to load information stored in the polymer memory cells into the DRAM semiconductor memory. Likewise, the information from the volatile DRAM semiconductor memory be transferred to the non-volatile polymer memory. By this, it may be achieved that the information stored in the DRAM semiconductor memory, or the state of the DRAM semiconductor memory available, respectively, prior to the switching off is stored in the non-volatile polymer memory. On switching on of the DRAM semiconductor memory, the information stored in the non-volatile polymer memory or the state available, respectively, prior to the switching off of the DRAM semiconductor memory may be again taken over in the DRAM semiconductor memory directly after the switching on. Thus, an instantaneous switching on of a system may be achieved without substantial time delay.

Problems solved by technology

The problem of the leaking currents in the memory capacitor existing with the DRAM memory concept, which may result in a loss of charge or a loss of information, respectively, has so far been solved insufficiently only by the permanent refreshing of the stored charge.

The flash memory concept, however, has the problem of restricted write and read cycles.

Moreover, relatively high voltages are needed with flash devices since the charges have to overcome a barrier layer.

As has been explained above, the DRAM semiconductor memory devices have the advantage of short write and read times, but the disadvantage of a volatile data content, which necessitates a permanent refreshing of the information stored.

In prior art, e.g. in US 2004 / 0016947 A1, combinations of DRAM semiconductor memories and FLASH memory devices have already been suggested, which, however, have the above-mentioned disadvantages of the FLASH memory devices.

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